Improved sieve



UNITED STATES PATENT OEEICE.

E. L. PRATT, OF BOSTON, MASSACHUSETTS.

I'MPROVED SIEVE.

Specification forming part of Letters Patent No. 59,450, dated November 6, 1866.

To all whom it may concern:

Be it known that I, E. L. PRATT, of Boston,

A county of Suiolk and State of Massachusetts,

have invented a new and useful Improvement in Sieves; and' I- do hereby declare that the following is a full, clear, and exact description of the construction and operation of the same, reference being had to the annexed drawings, making part of this specification, in which- Figure l is a top View; Fig. 2, a section and side elevation of the same. y

My improvement consists in the construction of a selfadj ustin g apparatus for more readily moving or stirring Hour or other article to be sifted in common or ordinary sieves.

My improved apparatus is constructed by attaching three or more arms, a c a, to a center or hub, O. These arms are attached by means of screws b b b, and left free to vibrate, so that the hub C can readily rise or fall to meet the elevation or depression of old or new sieves.

It will be observed that the arm a, in which the crank-pin d is inserted, is brought farther forward than the others, to give it a more steady motion and a wider bearing on the meshes of the sieve.

In use the arm a, next forward of the arm a, having the crank-pin d, receives milch the larger portion of the friction on the hoop of the sieve, and for this reason I have inserted or placed a small friction-roller.

ers may be placed to the other arms if thought desirable.

Similar roll- Were the arms a a a straight, the articles to be sifted would be too much thrown or impelled again st the hoop ofthe sieve. I therefore bend or corrugate them, so as to retain the article to be sifted in its proper position. These corrugations of the arms a c a also give a much Wider bearing-space to the arm over the meshes of the sieve, which gives to my improved apparatus all the advantages of a narrow bearing and a wide support in one and the same arm..

The application of this apparatus to an orl dinary sieve enables any person to perform a much larger amount of work in a given time.

To use this apparatus, iirst place itin an ordinary seive of suitable size, and then put in the article to be sifted. The apparatus is then turned around by means of the crank-pin d until the article to be sifted has passed through the meshes of the sieve.

Having described the construction and operation of my improved sifting apparatus, what lclaim as new,and desire to secure by Letters Patent, is-

The combination of the corrugated arms aaa with the center hub O, all operating within the hoop of the sieve, substantially as specified.

and described.

E. L. PRATT.

Witnesses y J AMES S. N EWELL, W. W. ABBOTT. 

